Extracted stay points:
laltitude	longitude	arriving time	leaving time
39.93748755589127 116.38987732326295 2009-04-05,08:24:58 2009-04-05,09:24:23
39.944404822580644 116.3756206774193 2009-04-05,10:05:33 2009-04-05,11:26:23
